1. Field of the Invention
Apparatuses consistent with the present invention relate to a patch antenna for local area communications. More particularly, the present invention relates to a patch antenna for local area communications having small size, high gain, wide bandwidth, and directionality.
2. Description of the Related Art
Recent developments of information and communication technology put emphasis on miniaturization and mobility of communication devices. Particularly, a mobile communication device with various functions provides diverse services to users through additional functions such as a wireless Internet access function using WLAN, a digital multimedia broadcasting (DMB) function enabling to view terrestrial or satellite programs, a position recognition function using GPS satellites, a camera, an MP3, and an RFID, in addition to a communication function which is a unique function of the mobile communication terminal.
Among those services, a new technology and service called mobile RFID (mRFID) is developing through the convergence of RFID system and mobile communications. The mRFID technology can read information from an external tag and provide useful information services to a user or forward information from the mobile communication terminal to another device through the tag of the mobile communication terminal, by mounting a tag, a reader, an antenna, and a processing module to a mobile communication terminal.
An RFID antenna adapted to the mRFID technique transmits and receives radio signals of frequency 908.5˜914 MHz in Korea and of 2.45 GHz frequency in Europe, whereas an antenna dedicated to communications of the mobile communication terminal transmits and receives radio signals of 850 MHz frequency. There is small difference between the domestic band for the RFID radio signals and the domestic band for the mobile communication radio signals. However, since a mobile communication antenna of a conventional mobile communication terminal uses the narrowband, it is difficult to transmit and receive even the RFID radio signals. Additionally, in Europe, it is more difficult to use one antenna because of the considerable difference between the RFID radio signal band and the mobile communication radio signal band. Thus, to implement the mRFID technique, the conventional mobile communication terminal uses the RFID antenna and the mobile communication antenna that are separately mounted.
However, when the RFID antenna and the mobile communication antenna are provided separately, it is inevitable that the mobile communication terminal will be large. This goes against the trend of current mobile communication terminal advancements, which attempts to miniaturize mobile communication terminals. Therefore, it is necessary to find a solution to avoid enlargement of mobile communication terminals through the miniaturization of RFID antennas.
It is advantageous that the antenna has wide bandwidth and high gain, and that a local area antenna with a specific purpose, such as RFID antenna, has directionality. Therefore, there is demand for an antenna having wide bandwidth, high gain, and directionality.